Augmentation of biodegradability of olive mill wastewater by electrochemical pre-treatment: Effect on phytotoxicity and operating cost

In order to exploit the fertilizer value of olive oil mill wastewaters (OMW), a novel method has been developed for its treatment. OMW effluents were pre-treated first by electrocoagulation using aluminum electrode and then by a biological process using a selected strain of Aspergillus niger van Tieghem. The effect of treatments was assessed through COD removal, reduction of total phenols, and decrease of phytotoxicity using durum wheat (Triticum durum) seeds. This sequential treatment scheme was capable of reducing concentration of organics, phenolics and phytotoxicity. The goal of this investigation was achieved, the phytotoxicity was completely removed and the germination index was 106% of OMW after sequential treatment. It can be concluded that the sequential process of OMW treatment might serve for the production of a fertilizer which is able to improve the growth of plants. These results are encouraging in the context of developing a low-budget technology for the effective management of OMW. (C) 2011 Elsevier B.V. All rights reserved.